【摘要】 本文观察了安定、戊脉安和PK11195对兔心乳头肌动作电位和收缩的作用,并比较了安定对兔与豚鼠心肌收缩作用的差异。安定(0.7×10^-6-22.4×10^-6mol/L)使兔乙乳头肌动作电位时程（APD）及钙依赖动作电位（Ca-AP）时程缩短,并使Ca-AP的最大上升速率(V_max)和幅值减小;安定还抑制兔与豚鼠心室乳头肌的收缩,相比之下对豚鼠的作用更明显。在戊脉安(2×10^-6mol/L)作用下,兔心乳头肌Ga-AP逐渐消失。提高溶液中Ca²⁺的浓度可拮抗安定和戊脉安的作用。PK11195(1×10^-6mol/L)可使安定对兔心乳头肌APD作用的剂量-反应曲线平行右移,且拮抗安定对Ca-AP的作用。预先加入PK11195(3×10^-6mol/L),则戊脉安不能取消Ca-AP。上述结果提示。（1）兔心乳头肌存在的苯二氮（艹卓）结合位点具有外周型苯二氮（艹卓）受体（BZR）的性质;（2）这种受体的激活可导致钙内流减少;（3）BZR的密度及反应性可能存在种属差异。更多还原

【Abstract】 Effects of diazepam, verapamil and PK11195 on the action potential and con-tractility of the rabbit papillary muscle were investigated. Some comparisons werealso made between the effects of diazepam on the contractility of the rabbit andthe guinea pig. 0.7--22.4×10^-6 mol/L diazapem shortened the duration of the action potential（APD） and calcium-dependent action potential（Ca-AP）, and decreased the maxi-mum rise rate as well as the amplitude of the Ca-AP in the rabbit papillary muscle,which was accompanied by a decrease of contractility. The effect of diaz-epam on the contractility was more pronounced in the guinea pig. 2×10^-6 mol/Lverapamil suppressed the Ca-AP of the rabbit papillary muscle, an effect thatcould be antagonized by increasing the external calcium concentration. Thecurve relating APD or contractility to diazepam dosage could be shifted to theright by 1×10^-6 mol/L PK11195. In the presence of PK11195, the Ca-AP wasmore resistant to the effect of verapamil. Our experimental results suggest: （a） Benzodiazepine binding sites in therabbit papillary muscle may act as peripheral benzodiazepine receptors; （b） Activa-tion of these receptors can result in a decrease of calcium influx; （c） Speciesdifferences may exist in the density and responsibility of this receptor.更多还原